1. Field of the Invention
The present invention relates to inspection apertures in insulation cladding, and more particularly to a method and structure for forming same.
2. Description of the Prior Art
Containment vessels of various forms are frequently provided with insulation cladding, leaving the containment structure obscured. As a result no inspection is possible of the integrity of the vessel walls, and corrosion and other structural deterioration is often not detectable at all. In the past various opening techniques have been devised through the insulation cladding to expose the vessel for inspection.
One prior art technique for vessel inspection access is described in U.S. Pat. No. 5,010,926 issued to Kurth et al, on Apr. 30, 1991. While suitable for the purposes intended, the foregoing structure allows for some insulation coefficient differential and there is therefore a consequent incidence of condensation, incurring an increased possibility of corrosion at the aperture itself. As result, the inspection access is not indicative of the overall state of the vessel, increasing the possibility of an unnecessary repair procedure.
For these reasons, it is preferrable to match the insulation characteristics of the inspection aperture with those of the cladding itself and to minimize all potential vapor migration to the vessel wall through the inspection cutout. One technique for effecting these objectives is described herein.